US4393686A - Circuit arrangement for a gas measuring and gas analysis apparatus - Google Patents

Circuit arrangement for a gas measuring and gas analysis apparatus Download PDF

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Publication number
US4393686A
US4393686A US06/298,015 US29801581A US4393686A US 4393686 A US4393686 A US 4393686A US 29801581 A US29801581 A US 29801581A US 4393686 A US4393686 A US 4393686A
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digital
input
measured
circuit arrangement
output
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US06/298,015
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Hans-Jorg Fengler
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Auergesellschaft GmbH
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Auergesellschaft GmbH
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Assigned to AUERGESELLSCHAFT GMBH, BERLIN, W. GERMANY A CORP. OF GERMANY reassignment AUERGESELLSCHAFT GMBH, BERLIN, W. GERMANY A CORP. OF GERMANY ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: FENGLER, HANS-JORG
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
    • G01N33/0004—Gaseous mixtures, e.g. polluted air
    • G01N33/0009—General constructional details of gas analysers, e.g. portable test equipment
    • G01N33/0062—General constructional details of gas analysers, e.g. portable test equipment concerning the measuring method or the display, e.g. intermittent measurement or digital display
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
    • G01D1/00—Measuring arrangements giving results other than momentary value of variable, of general application
    • G01D1/12—Measuring arrangements giving results other than momentary value of variable, of general application giving a maximum or minimum of a value

Definitions

  • the invention concerns a circuit arrangement for a gas measuring and gas analysis apparatus.
  • the basic object of the invention is to create a circuit arrangement with the lowest technological expenditure in order to be able, at any time, to reproduce or recall the maximum value of the gas concentration measured by the gas measuring and gas analyzing apparatus.
  • the measured-value storage makes it unnecessary to carry out a concentrated and continuous reading of the indicating device in a gas measuring and gas analyzing apparatus in order, for example, to be able to determine the often decisive maximum measured value of a gas concentration.
  • This is especially advantageous in the indicating device of a gas measuring apparatus with a ballistic indication behavior, whereby the measured value briefly attains a maximum, only to drop again after the combustion.
  • the reading of the indicating device is simplified by the incorporation of the measured-value storage since, after the measuring phase, it is required only to read the maximum value.
  • FIG. 1 presents a circuit arrangement in the form of a block diagram of the gas measuring and gas analyzing apparatus made in accordance with the invention with a maximum-value storage;
  • FIG. 2 is a schematic diagram which illustrates, by way of example, an embodiment of the invention.
  • the circuit arrangement for reproducing and indicating, at any time, at the indicating device B, the maximum value of the gas concentration measured by the measuring part (or sensor) A of the gas measuring apparatus consists of the maximum-value storage C, which is connected between the said measuring part A and the indicating device B and which consists of a digital and an analog circuit part.
  • a free-running oscillator 1 continuously pulses, at a high frequency, a binary counter 2 which is separated from a digital-analog converter 3 by a digital storage 4.
  • a digital comparator 5 compares the binary values of the counter outputs from the binary counter 2 with the inputs to the digital-analog converter 3.
  • An analog comparator 6 is connected to the input K 1 with the measured value input M E coming from the measuring part A, and to the input K 2 with the maximum value output of the digital-analog converter 3.
  • the analog comparator 6 actuates a digital logic section 7 which, in essence, consists of a logical connection of NOR gates which open or close the digital storage 4.
  • the maximum gas concentration stored in the maximum value storage C can be made indicatable on the indicating device B.
  • the analog comparator 6 When the voltage at the measured value input M E exceeds the stored maximum value M A , coming from the digital-analog converter 3 at the output of the converter, the analog comparator 6 then becomes positive or it switches over and the higher potential "H", that is the binary allocation "High Level", lies at the input of the NOR-gate G 1 .
  • the input E 1 of the NOR gate G 2 is primed with the lower potential "L", that is, with the binary “Low Level” allocation.
  • the NOR gate G 1 inverts the positive signal from the analog comparator 6.
  • the digital comparator 5 detects that the binary 8-bit information values of the input and output of the digital storage 4 correspond and are equal
  • the NOR gate G 2 becomes activated in that the output signal from the digital comparator 5 is delivered with the binary allocation 1 via the NOR gate G 3 to the input E 2 of the NOR gate G 2 .
  • the input E 1 of the NOR gate G 4 is charged with the higher potential "H” and opens the digital storage 4 via the NOR gate G 5 .
  • the last binary information to be stored during the switch-over phase is yielded by the blocked digital storage 4 to the digital analog converter 3.
  • the converted analog value can be measured at all times at the output of the converter 3. The above-described process is caused to begin anew as soon as this value is exceeded at the measured-value input M E of the indicating device.

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  • Chemical & Material Sciences (AREA)
  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • General Physics & Mathematics (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Medicinal Chemistry (AREA)
  • Food Science & Technology (AREA)
  • Biochemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Investigating Or Analyzing Materials By The Use Of Electric Means (AREA)
  • Arrangements For Transmission Of Measured Signals (AREA)
  • Investigating Or Analysing Materials By Optical Means (AREA)

Abstract

A circuit arrangement for an apparatus for measuring and analyzing gases which emits a signal when a specified gas concentration is exceeded and which is capable of recalling the maximum value of gas concentration measured. A binary counter acted upon by an oscillator is connected to a digital-analog converter via a digital storage, and a digital-comparator compares the binary values of the counter output from the binary counter and the input to the digital-analog converter. An analog comparator receives the measured value input from a gas measuring device and the maximum value output from the digital-analog converter, and the digital storage is opened via a logic section when the voltage at the measured value input is greater than the voltage at the maximum value output and the digital storage also has equal signals at the input and output thereof.

Description

The invention concerns a circuit arrangement for a gas measuring and gas analysis apparatus.
Known types of gas measuring and gas analysis devices release an optical or acoustical alarm when a specified gas concentration is exceeded. However, in such cases, the maximum value of the gas concentration can only be read once, and, in fact, only when immediately observing the indicating device. Since, after a short period of time, the value of the gas concentration can decrease again, a true measurement is not always possible. Another drawback that can reveal itself in the event of an accident, such as one occurring under ground, is that the decisive measured value leading to the accident can no longer be determined after the event, even though the gas measuring apparatus is undamaged.
The basic object of the invention is to create a circuit arrangement with the lowest technological expenditure in order to be able, at any time, to reproduce or recall the maximum value of the gas concentration measured by the gas measuring and gas analyzing apparatus.
This object is accomplished in accordance with the invention by the features presented in the appended claims.
The advantages to be gained by the invention reside, in particular, in the fact that the measured-value storage, made in accordance with the invention, makes it unnecessary to carry out a concentrated and continuous reading of the indicating device in a gas measuring and gas analyzing apparatus in order, for example, to be able to determine the often decisive maximum measured value of a gas concentration. This is especially advantageous in the indicating device of a gas measuring apparatus with a ballistic indication behavior, whereby the measured value briefly attains a maximum, only to drop again after the combustion. The reading of the indicating device is simplified by the incorporation of the measured-value storage since, after the measuring phase, it is required only to read the maximum value.
An embodiment of the invention is illustrated by way of example in the appended drawings and described in detail in the following, in which
FIG. 1 presents a circuit arrangement in the form of a block diagram of the gas measuring and gas analyzing apparatus made in accordance with the invention with a maximum-value storage; and
FIG. 2 is a schematic diagram which illustrates, by way of example, an embodiment of the invention.
As may be seen from FIG. 1, the circuit arrangement for reproducing and indicating, at any time, at the indicating device B, the maximum value of the gas concentration measured by the measuring part (or sensor) A of the gas measuring apparatus, consists of the maximum-value storage C, which is connected between the said measuring part A and the indicating device B and which consists of a digital and an analog circuit part.
A free-running oscillator 1 continuously pulses, at a high frequency, a binary counter 2 which is separated from a digital-analog converter 3 by a digital storage 4. A digital comparator 5 compares the binary values of the counter outputs from the binary counter 2 with the inputs to the digital-analog converter 3.
An analog comparator 6 is connected to the input K1 with the measured value input ME coming from the measuring part A, and to the input K2 with the maximum value output of the digital-analog converter 3.
The analog comparator 6 actuates a digital logic section 7 which, in essence, consists of a logical connection of NOR gates which open or close the digital storage 4.
By actuating a chargeover switch U from the setting a to b, the maximum gas concentration stored in the maximum value storage C can be made indicatable on the indicating device B.
In the following, a description is given of the mode of operation of the circuit arrangement illustrated in FIG. 2.
When the voltage at the measured value input ME exceeds the stored maximum value MA, coming from the digital-analog converter 3 at the output of the converter, the analog comparator 6 then becomes positive or it switches over and the higher potential "H", that is the binary allocation "High Level", lies at the input of the NOR-gate G1.
The input E1 of the NOR gate G2 is primed with the lower potential "L", that is, with the binary "Low Level" allocation. In other words, the NOR gate G1 inverts the positive signal from the analog comparator 6. At the moment the digital comparator 5 detects that the binary 8-bit information values of the input and output of the digital storage 4 correspond and are equal, the NOR gate G2 becomes activated in that the output signal from the digital comparator 5 is delivered with the binary allocation 1 via the NOR gate G3 to the input E2 of the NOR gate G2. The input E1 of the NOR gate G4 is charged with the higher potential "H" and opens the digital storage 4 via the NOR gate G5. By this means, there is attained a true "forward thrust" of the momentary maximum value. From this moment on, the contents of the counter or the counter information of binary counter 2 are passed directly on to the analog converter 3 which increases its output voltage until such time that the voltage of the measured-value input ME is reached. The digital storage 4 is then immediately closed via the gate connection of the logic section 7, since the input to the NOR gate G1 becomes "L", and the gates G1, G2, G4 and G5 change their logic states.
The last binary information to be stored during the switch-over phase is yielded by the blocked digital storage 4 to the digital analog converter 3. The converted analog value can be measured at all times at the output of the converter 3. The above-described process is caused to begin anew as soon as this value is exceeded at the measured-value input ME of the indicating device.
In order to be able to unequivocally determine the momentary maximum measured-value of an arbitrary point of the measuring range, it is advantageous to set the binary counter to zero by actuating a reset key 8 in order to bring the measured-value output MA to the level of the measured-value input ME, even when the latter has smaller values.
According to the provisions of the patent statutes, I have explained the principle of my invention and have illustrated and described what I now consider to represent its best embodiment. However, I desire to have it understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically illustrated and described.

Claims (5)

I claim:
1. A circuit arrangement for an apparatus for measuring and analyzing gases and consisting of a measuring part with an indicating and warning device, characterized by the provision of:
(a) a binary counter which is acted upon by an oscillator and which is connected to a digital-analog converter through a digital storage,
(b) a digital-comparator connected for comparing the binary values of the counter output from the binary counter and the input to the digital-analog converter,
(c) an analog comparator which is connected to a measured-value input from the measuring part and to a maximum value output of the digital-analog converter, the analog comparator connected to a digital section and adapted for actuating the digital logic section such that said logic section opens and closes the digital storage, and
(d) a chargeover switch located between the measuring part and the indicating device and connected for switching the maximum value output to the measured value input on the input of said indicating device.
2. A circuit arrangement in accordance with claim 1, characterized in that the digital-comparator forms a connecting link between the digital and analog portions of the circuit, and constitutes an AND-linkage with the digital-analog converter.
3. A circuit arrangement in accordance with claim 1, characterized in that said analog comparator is adapted to open the digital storage via the logic section when the voltage at the measured-value input is greater than the voltage at the maximum value output and when the digital storage has equal signals at the input and the output thereof.
4. A circuit arrangement in accordance with claim 1, characterized in that the digital logic section is a logic linkage consisting of NOR gates.
5. A circuit arrangement in accordance with claim 1, characterized in that a reset key is provided in the logic section which is connected to bring the binary counter to zero when actuated so that the measured-value output can be adjusted to the level of the measured-value input.
US06/298,015 1980-08-21 1981-08-31 Circuit arrangement for a gas measuring and gas analysis apparatus Expired - Fee Related US4393686A (en)

Applications Claiming Priority (2)

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DE3031555 1980-08-21
DE3031555A DE3031555C2 (en) 1980-08-21 1980-08-21 Circuit arrangement for a gas measuring and gas analyzer

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US4393686A true US4393686A (en) 1983-07-19

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DE (1) DE3031555C2 (en)
FR (1) FR2492105B1 (en)
GB (1) GB2082860B (en)
IT (1) IT1144826B (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5410908A (en) * 1993-12-20 1995-05-02 Data Instruments, Inc. Measuring the quantity of a gas in a tank
US5708190A (en) * 1996-04-02 1998-01-13 Ssi Technologies, Inc. Gas concentration sensor

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3243542A1 (en) * 1982-11-25 1984-05-30 Hans-Jörg Dipl.-Kfm. 4400 Münster Hübner Method and measuring instrument for measuring and processing characteristic quantities of the environmental atmosphere, particularly of concentrations of various gases in the below-ground air current
DE3327154A1 (en) * 1983-07-28 1985-02-14 Hans-Jörg Dipl.-Kfm. 4400 Münster Hübner METHOD FOR MEASURING INDICATORS OF THE ENVIRONMENTAL ATMOSPHERE, IN PARTICULAR CONCENTRATIONS OF EXPLOSION HAZARDOUS GASES IN THE UNDERGROUND CURRENT FLOW
DE3643450A1 (en) * 1986-12-19 1988-06-30 Diehl Gmbh & Co Circuit arrangement for determining an extreme value
US5184500A (en) * 1990-03-20 1993-02-09 J And N Associates, Inc. Gas detector

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4064498A (en) * 1975-10-28 1977-12-20 Consolidation Coal Company Electrical circuitry for detecting a combustible mixture of gas in a mine atmosphere

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1445837A (en) * 1972-10-13 1976-08-11 Sira Institute Apparatus for recording the maximum or minimum value of a measurable variable
JPS5811079B2 (en) * 1976-10-05 1983-03-01 株式会社東芝 X-ray source device
DE2829931C2 (en) * 1978-07-07 1985-11-21 Auergesellschaft Gmbh, 1000 Berlin Portable gas measuring and warning device

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4064498A (en) * 1975-10-28 1977-12-20 Consolidation Coal Company Electrical circuitry for detecting a combustible mixture of gas in a mine atmosphere

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5410908A (en) * 1993-12-20 1995-05-02 Data Instruments, Inc. Measuring the quantity of a gas in a tank
US5708190A (en) * 1996-04-02 1998-01-13 Ssi Technologies, Inc. Gas concentration sensor

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Publication number Publication date
IT8168137A0 (en) 1981-08-20
FR2492105B1 (en) 1985-06-14
GB2082860B (en) 1983-10-12
GB2082860A (en) 1982-03-10
DE3031555A1 (en) 1982-03-18
FR2492105A1 (en) 1982-04-16
IT1144826B (en) 1986-10-29
DE3031555C2 (en) 1985-03-14

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